Seems I'm conflating the children of liberty too, because I forgot who Manchester killed. That leaves the bar guy (Petrocelli?) the only one of his victims who wasn't on a certain path to get blood on his hands. Or was he? Still, summarily executing someone before they had committed their act of violence leaves uncertainty as to how exactly things were going to go—certain enough to stop them, but not for much else, especially not for cold bloody murder.Still, you're right that the men he shot intended to break in and assault or murder the occupants of that house, as part of a systematic terrorist attack, essentially a pogrom.
I doubt any viewer is viewing Manchester as a positive character, from the show's cues, to killing people at least one of whom without even an indication he would commit violence, to abducting Kara and being accessory to her attempted assassination, and then to mind raping Jon. Pretty clear.
Both him and Gambi murdered someone after they were no longer an immediate threat to someone's life, but after both of said victims had been a threat to someone's life. Whether it was their own or not, the motives are in the same ballpark, even if Manchester crossed way more lines, allowed the murders to act as his pain release and seemed to have little concern if he got the right people – so he's like Oliver all right.Yes, they are not Boy Scouts, but no one can make a straight-face argument that places the motives for Oliver and/or Gambi's actions on the same level as Manchester Black.